1. Field of the Invention
This invention relates to an apparatus for the removal of air and other gases dissolved and entrained in liquids. More particularly it relates to the continuous removal of air and other gases from viscous liquid solutions such as viscose and other derivatives of cellulose.
2. Description of Related Art
Gas and air may become entrained in liquids in the form of bubbles, such as in the process of preparing liquid viscose solutions for the spinning of synthetic fibers. Should these gases and air bubbles be permitted to remain, broken filaments in the spun yarn would result when the viscose solution is extruded through the holes of spinnerets. Yarn thus produced would have a varying number of filaments and would therefore not be of uniform quality.
There are numerous processes for removing entrained air from liquids. For example, U.S. Pat. No. 2,684,728, discloses an apparatus for removing air from a viscose solution wherein the viscose solution is boiled and then continuously fed to a channel and trough from which the liquid overflows to spread as a thin film over supporting surfaces such as the interior wall of a tank and the exterior wall of a bell-shaped cylinder located within the lower portion of the tank.
U.S. Pat. No. 2,306,265, discloses an apparatus for degasifying viscous compositions by momentarily exposing a maximum surface of the material in the presence of a vacuum and then quickly returning the material to a body of minimum surface to prevent the evaporation of moisture and other volatile components. In this apparatus, the composition to be degasified uses a deaerator insert where the composition passes by gravity feed through channels and, upon emerging from those channels, is spread as a thin film on the inside wall of a cylindrical chamber that houses the insert. This film is thinner than the thickness of the gas bubbles entrained in the liquid so that the bubbles are caused to pop by the vacuum in the deaerator.
Attempts have been made to increase the available surface area for removing gases entrained in liquids. For example, U.S. Pat. No. 2,041,059, discloses an apparatus wherein a gas-containing liquid is subjected to a partial vacuum and then flows as a thin film over a succession of gently sloping conical surfaces with alternate cones inverted with respect to the others to increase the surface area and the points from which the gases evolve so as to further promote the rapid emission of gases from the liquid. However, a problem with these conical surfaces is that the thickness of the film is greater near the bottom of the cone than near the top of the cone and this increased thickness may be too large to allow the entrained gas to escape.
The inventors of the present invention have discovered an improved apparatus for removing entrained air and gases from liquids which provides a insert for a deaerator which provides a large surface area for removing gases entrained in liquids which overcomes the problems associated with the prior art.
The present invention is directed to an insert for a vacuum deaerator that includes means for receiving a liquid having gas entrained therein, means for distributing the liquid to a gas-disentrainment surface, the distributing means being connected to the receiving means to permit the liquid to flow from the receiving means to the distributing means, and at least one fin attached to and extending downwardly from the distributing means to receive the liquid from the distributing means and to provide a gas-disentrainment surface to allow removal of entrained gas from the liquid.